Clipping a bag shut with a bag or binder clip is pretty easy, but if you need to seal a bag of bagels you don't need anything at all. Clever redditor aboyne42 figured out that you can lock air out just as effectively by shoving the bag into the bagel holes.

The downside likely comes when you're running low on bagels and you have a lot of bag but not much in the way of bagel holes to push the bag into. That said, if you're in a pinch and you want your bagels to last a bit longer, you don't need any special tools to keep the bag shut-just the bag itself.